1. Field of the Invention
This invention generally relates to data transfer over wired, wireless, and/or optical transmission channels. More particularly, this invention relates to reception of ultra-wideband signals in the presence of interference.
2. Background Information
As computing and communications applications become richer and more complex, there is a need to transfer information between communicating devices at higher and higher data rates or at lower cost and power consumption. Use of such devices may include large data transfers and/or multimedia applications or distributed sensor networks. For example, multimedia applications may handle multiple simultaneous streams of high-definition audio and/or video coming from devices such as business/entertainment systems and gateways necessitating high-speed connectivity between communicating devices.
Increasingly, such devices are used in mobile and changing environments, where untethered connectivity is not only a convenience for the user, but can be a functional requirement, for example, cellular phones. Wireless connectivity can provide enhanced capabilities, ease of use, and may result in cost savings and increased productivity. Accordingly, there is a need for high-speed wireless connectivity and very low cost/low power consuming devices.
For consumer electronics devices, cost and complexity of transmitter and receiver implementations are important considerations as they can significantly contribute to the device production cost. Such devices therefore benefit greatly from low-cost high-speed wireless connectivity.
Most existing wireless communication schemes transfer data by modulating continuous-wave carriers. In many cases, a portion of the radio-frequency spectrum is reserved for the exclusive use of the scheme. Data transfers may be conducted over very narrow frequency bands in an attempt to occupy less of the frequency spectrum. However, such schemes may be susceptible to increases in background noise level and to multipath interference. Some narrowband schemes may also interfere with other systems (e.g. due to a higher concentration of energy in the particular frequency band being used).
Therefore there is a need for schemes for low-cost high-speed low-power wireless devices, which are less susceptible to multipath interference. Ultra-wideband (UWB) communication methods transmit information by spreading energy over a large portion of the radio frequency spectrum. Ultra-wideband communications transmit over a very wide bandwidth with very low power density. Thus, while ultra-wideband schemes are less susceptible to multipath interference, their performance can degrade in the presence of narrowband transmissions, which are in close proximity or which transmit signals with higher power. It is prudent, therefore, to provide methods to mitigate the effects of these narrowband transmissions on the ultra-wideband communication process